Spiders are often mistaken for insects, but there’s a clear distinction between the two.
They belong to the arachnid family, which also includes other creatures such as mites, ticks, and scorpions.
Insects, on the other hand, fall under their own separate classification.
Arachnids have two main body segments, eight legs, and no antennae or wings, while insects have three body sections, six legs, and often possess antennae.
For example, the black widow spider is an arachnid with a venomous bite, while the common housefly is an insect without such a threat.
This distinction is crucial in understanding the biology and behavior of these creatures.
Are Spiders Insects? Debunking the Myth
Many people often wonder if spiders are insects. Let’s clarify this misconception by highlighting their differences.
Spiders belong to a group called arachnids. They are closely related to ticks, mites, and scorpions.
In contrast, insects are part of a separate category in the animal kingdom.
Here’s a comparison table to illustrate their differences:
| Feature | Spiders | Insects |
|---|---|---|
| Body Sections | 2 | 3 |
| Legs | 8 | 6 |
| Wings | None | 0, 2, or 4 |
| Antennae | Absent | Present |
- Spiders have two main body sections: the cephalothorax and the abdomen.
- Insects possess three body sections: the head, thorax, and abdomen.
In terms of legs, spiders have eight, while insects have only six. Moreover, spiders don’t have wings or antennae, both of which are features commonly seen in insects.
Interestingly, spiders and insects have a unique predator-prey relationship.
For instance, spiders mostly feed on insects like grasshoppers, flies, moths, and leafhoppers, and are beneficial to agricultural lands by controlling crop-damaging pests.
In summary, spiders and insects have distinct characteristics that set them apart, and it is important to recognize these differences to understand their roles in nature.
Anatomical Differences Between Spiders and Insects
Body Parts
Spiders and insects are both classified as arthropods, but they present some major anatomical differences.
Insects’ bodies consist of three main parts: head, thorax, and abdomen. On the other hand, spiders have only two body segments: cephalothorax and abdomen.
- Insects: head, thorax, abdomen
- Spiders: cephalothorax, abdomen
Legs
Another crucial distinction involves the number of legs, as spiders and insects differ in this aspect as well.
- Insects: 6 legs
- Spiders: 8 legs
This difference in leg count further distinguishes these two types of creatures, with insects like butterflies or bees walking on 6 legs, while spiders like the brown recluse or black widow have 8 legs.
Eyes
The number of eyes is yet another clear distinction between spiders and insects. Insects typically have two compound eyes, while spiders possess sizes varying from two to eight eyes.
For example, the brown recluse has three pairs of eyes, while most spiders have four pairs.
| Creatures | Number of Eyes |
|---|---|
| Insects | 2 (compound eyes) |
| Spiders | 2 to 8 (simple eyes) |
This table highlights the differences in the number of eyes among insects and spiders, emphasizing their distinctive characteristics.
Behavioral Differences
Feeding Habits
Spiders and insects have distinct feeding habits that differentiate them.
Spiders are mostly predators, feeding on other insects and small animals, while insects have a wide range of feeding habits, such as herbivorous, carnivorous, or detritivorous.
Jumping spiders, for example, can identify biological motion to locate their prey, while ants feed primarily on plant material and aphids.
- Spiders: Predators, capture prey using silk webs or by hunting
- Insects: Diverse diet, e.g., plants, dead organisms, or other insects
Reproduction
Reproduction in spiders and insects also varies significantly.
Most insects undergo a metamorphosis during their development, which can include distinct stages like egg, larva, pupa, and adult.
Butterflies, for instance, undergo a complete metamorphosis involving these four stages.
On the other hand, spiders do not undergo metamorphosis. They develop through a series of molts, shedding their exoskeleton as they grow.
After an adult male spider finds a suitable mate, it transfers sperm to the female using specialized structures called pedipalps.
| Spiders | Insects | |
|---|---|---|
| Feeding | Predators | Diverse (plants, other insects, etc.) |
| Development | No metamorphosis (molts) | Metamorphosis (egg, larva, pupa, adult) |
The Role of Spiders in the Ecosystem
Predation
Spiders play a vital role as predators in the ecosystem. They primarily feed on insects, helping to keep their populations in check.
For example, some common prey for spiders are mosquitoes, flies, and moths.
A few benefits of spiders in predation are:
- Reduction of pests in gardens and agricultural fields
- Maintaining balance in ecosystems
- Preventing overpopulation of insects
Pest Control
Spiders are natural pest controllers. They help control populations of insects that can be harmful to plants, like aphids, caterpillars, and beetles.
Here’s a comparison table of two common spider species and their role in pest control:
| Spider Species | Target Pests |
|---|---|
| Garden Spiders | Aphids, grasshoppers, flies, and beetles |
| Jumping Spiders | Flies, mosquitoes, small beetles, and moth larvae |
In conclusion, spiders play a crucial role in ecosystems by controlling insect populations, reducing pests, and maintaining balance.
Types of Spiders
Common House Spiders
Common house spiders are arachnids, not insects. They are closely related to mites, ticks, and scorpions, and have distinct characteristics like:
- Two main body sections: cephalothorax and abdomen
- Eight legs
- No antennae
- No wings
Some examples of common house spiders include:
- American House Spider
- Cellar Spider
- Wolf Spider
Venomous Spiders
Some spiders, such as the brown recluse and black widow, are venomous. Their venom can be dangerous to people. Key differences between the two venomous spiders are:
| Feature | Brown Recluse | Black Widow |
|---|---|---|
| Color | Brown | Black with red or orange hourglass markings |
| Markings | Dark violin-shaped marking on the head | None |
| Eye Structure | Six equal-sized eyes | Eight Eyes |
Keep in mind that not all spiders are venomous and that most spiders are harmless to humans.
Conclusion
Spiders are not insects, but they are closely related to them. Spiders belong to the class Arachnida, which also includes scorpions, mites, and ticks.
Spiders have eight legs, two body segments, no antennae, and no wings. Insects have six legs, three body segments, antennae, and usually wings.
Spiders and insects are both invertebrates that have exoskeletons, jointed appendages, and compound eyes.
Spiders and insects are diverse and important animals that share some similarities and differences.
Reader Emails
Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about the difference between spiders and insects.
Scroll down to have a look at some of them.
Letter 1 – Mudang Spider of Korea
Hi,
I did a bit of hunting round this year to try and find the name of an interesting spider I see frequently in Korea (see attached photographs). It turned out to be the Nephila clavata or golden orb weaver, common to Korea and Japan.
I stumbled across you site recently. Someone asked what the Korean name of this spider is and what it means. The Nephila clavata or golden orb weaver is called a
or “mudang gumi” in Korean (I have attached a .jpeg file of the Korean text in case your computer cannot read Korean). This means, roughly, “fortune teller spider” or “shaman spider”.
“Mudangs” are Korean fortune tellers, usually female, who use the time, day, month and year of one’s birth to make predictions or assess the compatibility of a couple before marriage..
Regards,
H.L.
Hi H.L.,
Thanks for the fascinating account of this marvelous spider.
Letter 2 – Linyphia species?
Great site, I enjoyed cruising through all the pictures. I live in Fort Collins, Colorado and have captured several of these orange and black (ant mimic?) spiders. They are very fast and I feed them small grasshoppers.
They are a little bigger than a nickel or so. If you can tell me anything about them as well as what they actually are I would greatly appreciate it. A picture of one of them is attached. thank you,
David Huntwork
Hi David, It appears to be a member of the genus Linyphia. These are Sheet-Web weavers and several species are colored like your specimen, though the coloration is variable. Linyphia insignis resembles your spider most in shape.
Letter 3 – Male Nephila Clavipes
This spider has spun a web outside our patio door and we can’t find a match for it on the internet, any ideas??? It’s about the size of a quarter including leg span. We live in northeast Florida. Thanks for your help!
Tommy
Hi Tommy,
We frequently get images of female Nephila clavipes, but never a male. The males are about 1/100 the size of the enormous females. These spiders are also known as Silk Spiders or Banana Spiders.
Letter 4 – Micrathena sagittata, Female
This spider is in my friends house and I cannot find anything or any pictures that can tell us what kind it is and/or anything about it. Can anyone help me identify this and if it is harmful?
You have a female Micrathena sagittata or Arrow-Shaped Micrathena. It has a signature body shape and is not easily confused with other spiders.
The species is common in the south and also reported in Massachusetts and Connecticut. It makes a web that is a small symetrical orb in low bushes. The spider is not harmful.
Letter 5 – Mygalomorph
Hi,
We found this spider in our house in Marin County, Northern California. We just had some early season rain showers and am wondering what kind of spider this is. The small object in the picture is a bee. Thanks for your help,
Christian
Hi Christian,
We are only able to provide you with a general answer. This is one of the primitive Mygalomorphs, the Infraorder that includes Tarantulas, Trapdoor Spiders and Purseweb Spiders. This looks to be a Tarantula. Sorry we can’t be more conclusive.
Letter 6 – Nephila clavipes
Can you tell me the species of the spider in the attached pic? It ‘s about 4-5 in. in diameter. The web was huge and intricate. It’s legs are purple and yellow striped. I took this picture in Savannah, Ga. I know that it is not a bug, but wonder if you can still help.
Thanks.
Nephila clavipes is also known as a Silk Spider because of the strength of its web, and Banana Spider because of the coloring of its body. Your spider is a female. Males are tiny, the females weighing about 100 times more.
Letter 7 – Pisaurina mira
This little beast parked itself tightly into our daughter’s playscape. We don’t usually get a lot of large spiders up here in northeast CT, so we figured we would ask some experts if this thing is dangerous.
We need to know soon as about a thousand of its infant minion have just burst forth from the joint where she’s nested!
Thanks!
Dave
Hi Dave,
Sorry for the long delay in answering. No, you should not be concerned. You have a wandering spider known as Pisaurina mira. These spiders do not build webs, but stalk their prey. They only build webs to care for their young. Though many spiders will bite when provoked, they are not aggressive.
Comstock writes:
“This is an extremely variable species in colour and in size. Full-grown specimens measure about one half (ed. note excluding legs) inch in length. In the more common type the body is light brownish yellow, with a wide darker and browner band on the middle of both cephalothorax and abdomen; on the cephalothorax the edges of the band are nearly straight, but on the abdomen they are undulating.
The band is bordered on each side by a white line. This is a common species throughout the eastern part of the United States, and one that frequently attracts attention on account of its beauty.” I hope your spider hasn’t met with an untimely end because of our tardiness.
Letter 8 – Seven Spiders from Dotty!!
I just discovered your terrific web site while trying to identify some spiders I’ve seen in my yard. I’m sending 7 images in two different emails. Is it OK to send several at once? I didn’t find any guidelines regarding submittal. I’ve tried and tried to identify these spiders, without any luck.
I can send any of these images in a higher resolution if you need them for identification. Thank you greatly for your help.Thanks. I live in Wichita, Ks,, and keep my yard in a naturalized state. BTW, I’m very impressed with your (tactful) efforts to educate those who have (usually out of ignorance) killed the species in the photos they send.
I have made it my goal to learn about everything that lives in my yard (flora and fauna). In the process, I’ve grown to love them all, even the scariest-looking insects. Problem is, I search and search and just can’t find any identification for many of them.
Regards,
Dotty
Hi Dotty,
Identifying all 7 of your spiders is a daunting task. We will try to get them all for you. This one is easy since we identified it last year. Herpyllus vasifer is found under stones and rubbish on the ground, between boards, and in crevices in dark places. It runs with exceeding rapidity. It is widely distributed in the U.S.
The photo above is probably a Running Crab Spider from the genus Philodromus.
Update
September 9, 2010
Since posting this letter many years ago, we have learned that Herpyllus vasifer is now classified as Herpyllus ecclesiasticus, the Eastern Parson Spider.
Letter 9 – Shore Spider
I understand you are very busy, but I thought I had correctly identified this spider (found on the banks of a creek with numerous individuals scampering about the rocks as well) found in western Pennsylvania.
I had suspected that this was a fishing spider, but another individual from our organization alerted me that it was incorrectly identified. So, I did a little more research and came up with a second guess: shore spider ( Pardosa milvina ) of the wolf spider family. Is that correct? Thank you very much,
Kylie
Hi Kylie,
We are impressed, and we concur that you have properly identified the Shore Spider, Pardosa milvina, based on images posted to BugGuide.
Letter 10 – Spectacled Spider
Hello,
I found this spider in my back yard in CT hiding in the corner of my daughters swing set behind a beautiful web. Can you identify it?
Best Regards,
Mike
Hi Mike,
You definitely have an Orbweaver from the genus Araneus, and we believe it to be the Spectacled Spider, Aranea gigas conspicellata. The black markings on your spider are very pronounced. She is a female and harmless. Thanks for sending the beautiful photo.
Letter 11 – Spider Eggsacs
Hey,
I thought of you guys when I saw this pair of rather large egg sacks on a utility box next to a garden. They are each about 1″ wide by almost 2″ tall. Any ideas on what will crawl out? Thanks,
Jerry
Hi Jerry,
These Eggsacs belong to some type of Spider, but we cannot tell you what. Several hundred Spiderlings will emerge.
Letter 12 – Spider Exhibit at Natural History Museum of Los Angeles County
Humph. Pretty cool. I wonder if the bug man knows about this…
Susan Lutz
October 15, 2010
Spiders roam free at new L.A. museum exhibit
Winston Lutz
Letter 13 – Spider from Colorado
Location: fort morgan, colorado
April 12, 2013 8:36 pm
Please help, I have 4 children and one has been saying his backside hurts (he sleeps on the floor because he hates his bed) and I found this today in my basement bathroom. Is it dangerous, and should I have my son checked?
Solid brown, no stripes I can see.
Signature: Dunderwood
Dear Dunderwood,
We are relatively certain this is not a dangerous spider, however, we do not know its identity, which is why we are contacting Mandy Howe.
Hi Mandy,
Here is a distraught parent of four. Please help alleviate the anxiety with an identification.
Letter 14 – Spider from Indonesia
Location: Gunung Manglayang Cilengkrang 40615, Indonesia
March 26, 2013 12:34 am
Hello Daniel,
3.24.2013. I met this guy hiding under a leaf at night hunting photo at Manglayang Mountain, West Java, Indonesia, first time seeing this one. The size is not more than 2 cm from toe to toe and this guy had a lovely abdomen color and pattern.
Signature: Mohamad Idham Iskandar
Hi again Mohamad,
Thanks to the nice facial view, someone with more experience at spider eye arrangements might be able to provide you with a family on this Spider. See BugGuide for Spider Eye Arrangements.
Letter 15 – Spider from Vietnam
Location: Vietnam (Phong Nha Ke Bang National Park)
January 26, 2014 9:33 am
Dear Bugman,
I’ve been trying to identify this spider I saw in Vietnam (the Phong Nha Ke Bang area) in 2012, but have not yet succeeded. Is the photo of enough to identify it? As a fairly new bug enthusiast any information you can help with would be great.
Thank you!
Signature: Sarah
Hi Sarah,
Do you have any additional images of this Spider? This is not the ideal camera angle for an identification, but it is sure an interesting looking Spider. We will post your photo and try to research its identity.
It reminds us of a Huntsman Spider or Giant Crab Spider in the family Sparassidae. Unfortunately, it is difficult to make out the eye pattern arrangement which is one of the best means of identifying the different spider families.
Hi Daniel,
Thank you for looking at the picture so quickly!
Unfortunately this was the only angle I got – it was peeking out of a hole under the path I was walking on (also was before I knew what was needed to identify spiders).
The closest I thought too was a Huntsman but the colouring on this one seemed quite distinct – I love the distinct black feet (must learn the technical terms!) on this spider.
Thanks for the assistance, I’ll keep researching and fingers crossed too.
What a wonderful site WTB is.
Kind regards,
Sarah
Letter 16 – Spiderlings
sorry about the crappy photo. These are tiny tiny spiders (or at least I think they are spiders). The webs are outside, usually in the legs of our deck furniture. They are dense webs (not the usual orb-like webs) and are just packed with a multitude of little spiders.
They are feaking us out. Can you help us identify them? If you can, should we give into our gut reaction to erradicate these colonies or should we revert to our ‘spiders are our friends unless proven dangerous’ philosophy.
Thank you
D. Rodrigues
Hi D.,
Your newly hatched spiderlings should begin to balloon away soon. They will climb to the highest point nearby and release a strand of silk and let the wind carry them away.
We just observed a similar phenomenon in Ohio and sadly did not have our camera. The do appear to be young orb weavers, but it is difficult to be certain. Spiders are your friends.
Letter 17 – Spider Nest
Location: Clayton, ca
October 7, 2012 1:59 pm
Hi, my dad found this strange egg sac in one of his plants about a month ago. Whatever left it also seemed to weave the leaf together. Any idea what left this behind? Thanks!
Signature: Sincerely, Jared
Hi Jared,
The pleating of the leaf in your photograph is most unusual and not something we recognize. We are posting your photo and inquiry in the hopes that one of our readers will recognize this nest. We are also contacting Eric Eaton to see if he has any opinion on the potential architect of the nest.
Eric Eaton Responds
Daniel:
Hm-m-m. The silk structure looks “spidery” to me, like an overnight retreat for some kind of hunting spider. I think the accordion pattern of the fused leaf is something else going on that is unrelated. The spider just took advantage of the nook created.
Eric
The post Are Spiders Insects? Debunking Common Misconceptions appeared first on What's That Bug?.
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